Search

Patterns of drinking and responding for ethanol (EtOH) and saccharin (SACC) were examined in the alcohol-preferring P rat using various limited-access paradigms. Adult female P rats (n = 10-20) were given 2-h access to EtOH (10-13% v/v) and SACC (0.0125% g/v) concurrently each day, or each solution individually on alternate days. Total 2-h SACC intake was significantly greater than EtOH under both concurrent (12+/-2 vs. 7+/-0.8 ml, p<0.05) and alternate-day access (18+/-1.6 vs. 10+/-0.5 ml) conditions. Under both conditions, however, EtOH intake (over 55% of the total) in the first 15 min was significantly greater than that of SACC (<25% of total). In an operant paradigm, total responding for EtOH (124+/-29) and SACC (114+/-7) under 2-h alternate-day conditions did not differ, but 65% of total EtOH responding occurred during the first 20 min versus less than 45% for SACC (p<0.05). Increasing response requirements (FR-1 to FR-5) did not significantly alter the total number of EtOH reinforcements, but decreased the total number of SACC reinforcements by approximately 50% (p<0.05). Increasing the EtOH concentration from 15% to 35% decreased the number of reinforcements approximately 50% but did not decrease the estimated g/kg EtOH intake. Increasing the SACC concentration from 0.0125% to 0.05%, however, nearly doubled the number of reinforcements. The greater preference for EtOH versus SACC during the initial part of the access period, together with the maintenance of EtOH intake in g/kg when the response requirements and the EtOH concentration were increased, suggests that EtOH intake is motivated by pharmacological consequences. Therefore, different motivational factors appear to underlie EtOH and SACC intake of the P rat. Furthermore, the pattern of EtOH intake and responding displayed by the P rat may be the result of a "bout-" or "binge-" like loss of control under restricted EtOH access conditions.

The specific question was how prenatal and/or postnatal experience with ethanol influences cardiac and behavioral responses to the odor of ethanol on postnatal day (PD) 16. In each of two experiments, pregnant rats were given ethanol or water on gestational days 17-20. Offspring were exposed on PD12 to one of three conditions: intragastric administration of 6% ethanol, indirect exposure to ethanol from littermates, or no treatment. Results of Experiment 1 indicated that, regardless of prenatal ethanol exposure, 16-day-olds exposed on PD12 either directly or indirectly to ethanol expressed a greater increase in HR in response to ethanol odor than pups not postnatally exposed to ethanol. In Experiment 2, in which a lower ethanol dose was used postnatally, an interaction between pre- and postnatal ethanol exposure was observed; that is, pups exposed pre- and postnatally to ethanol showed the greatest increases in HR and the smallest increases in motor activity in response to ethanol odor. In both experiments motor activity was dissociated from increases in HR. The results are discussed in terms of what is learned, prenatally and postnatally, in association with the chemosensory properties of ethanol.

Neonatal alcohol exposure during the first 1-2 weeks of age is known to produce subsequent behavioral hyperactivity in rats. However, little is known about the effects of alcohol exposure during adolescence on subsequent adult behavior. In the present study, male and female P rats had free access to 10% alcohol during adolescence (3-8 weeks of age). After 8 days of abstinence, their behavior was evaluated in the cross-maze and in the inescapable slip funnel tests during the 10th week of age. Two-way ANOVAs revealed significant effects of alcohol drinking on several variables. Compared to alcohol-naive rats, the alcohol-exposed group started exploration earlier (3.5 +/- 0.3 vs. 5.4 +/- 0.7 s, p = 0.03) and made fewer defecations. In the slip funnel test, the alcohol group spent more time immobile (130 +/- 7 vs. 107 +/- 5 s, p = 0.01) and less time attempting to escape out of the funnel (11 +/- 2 vs. 28 +/- 5 s, p = 0.002) than the control group. Overall, the results suggest that the effects of alcohol drinking by P rats during adolescence on subsequent behavior are to reduce novelty-induced anxiety (cross-maze test) and lower response to stress induced by an inescapable situation (slip-funnel test).

The impact of rearing condition was assessed in Sprague-Dawley dams given 40 mg/kg cocaine (C40) or saline (LC control) subcutaneously (SC) from gestational days 8-20 and their offspring. Treated pups reared by their biological dams (LC/LC; C40/C40), treated pups reared by surrogate dams (FOS/LC; FOS/C40), and foster pups raised by treated dams (LC/FOS; C40/FOS) were examined. On postnatal day 7 (P7), pups received either 0 (unpaired) 2, 3, or 4 pairings of an odor and footshock and were tested for their aversion to this odor. Foster and LC pups, regardless of rearing condition, exhibited significant odor aversions following either 2, 3, or 4 training trials. In contrast, C40 pups reared by surrogate dams required 4 trials to acquire the aversion, and C40 pups reared by their own dams did not exhibit conditioning even after 4 trials. At P17, no differences were seen among the groups in the aversion formed to an auditory or an olfactory stimulus that was paired with footshock. At P60, shock-elicited aggression among pairs of siblings was examined. Regardless of prenatal exposure condition, offspring reared by dams given cocaine showed a decreased latency to the first aggressive contact, an effect that was evident without any alteration in shock sensitivity. Together these data suggest that being reared by a dam previously exposed to cocaine has an impact on offspring behavioral function apart from the effects of prenatal cocaine exposure per se. The implications of the data regarding the cognitive performance of pups exposed prenatally to cocaine are also discussed.